George w



(No Model.)

G. W. BAIRD.

STEAM GENERATOR 0E EVAPORATOR. No. 450,361. Patented Apr. 14,1891.

WITNESSES INVENTOR UNITED STATES PATENT OFFICE.

GEORGE W. BAIRD, OF WASHINGTON, DISTRICT OF COLUMBIA.

STEAM GEN ERATOR OR EVAPO RATO R.

SPECIFICATION forming part of Letters Patent No. 450,361, dated April 14, 1891.

Application filed September 26, 1890. Serial No. 366,209. (No model.)

To aZZ whom it may concern:

Be it known that 1, GEORGE W. BAIRD, an engineer officer in the Navy of the United States, residing at Vashington, in the District of Columbia, have invented certain new and useful Improvements in Steam Generators or Evaporators, of which the following is a specification.

The object of my invention is to supply pure water for steam-boilers and other purposes; and it is an improvement on my device shown in my patents of August 23, 1887, No. 368,642, and December 24,1889, No. 417,803.

Referring to the drawing, the figure is an elevation, part in section.

A is the evaporator 01- generator, provided with the U shaped tubes E, the ends of which enter the steam-chests J, the lower chest being connected to the trap F by a pipe, by which the water of condensation is automatically discharged from the tubes E. Steam is supplied to the chest J by the pipe K, which leads from a boiler or receiver.

G is a brine-pu'mp, H the water-gage, and I the feed-pipe to the evaporator.

B is a condenser formed by a coil 0 within a casing, the upper end of the coil being connected by pipe R to the steam-space of the generator, and is provided with the valve P. The lower end of the coil leads to the airpump 0, which pumps the water condensed in the coil through the filter D and out through pipe Q to the boiler or storage-tank.

By means of a circulating-pump (not shown) sea-water is pumped in the condenser at opening L and out at M, and is discharged at any convenient point. Part of the circulating water, the temperature of which -has been raised by contact with steam-c011 1s fed into the generator through pipe I by openin valve-N,the-vacuum causlng the water to enter. .7

S is an aerator placed between the condenser and evaporator, and is formed by the end of the pipe R entering the end of co1lO,leav1ng sufficient space for the pump to draw in air through check-valve H when a vacuum is formed.

The operation is as follows: Steam from a boiler or receiver is entered into steam-chest J through pipe K. This steam heats coil E. Air-pump O isstarted, which creates a vacuum in the condenser and in the evaporator, say, of twenty-five inches of mercury. The

circulating-pump (not shown) forces water into condenser at 1 and out at M. By opening valve N a feed is obtained. This feedwater is vaporized by the heat of the coils and is boiled at a temperature, due to the vacuum, about 135 Fahrenheit. This vapor passes to the condenser, where it is condensed in contact with the cold coils. It is then pumped throug the filter D and is discharged at Q, whence it is delivered to tanks or other storage. If sea-water be used for circulation and for feeding the evaporator, the water in the evaporator becomes denser and denser, owing to the solid matter in solution becoming proportionately greater. At the temperature employed in steam-boilers the water precipitates the sulphate-of-lime scale on the heating-surfaces; but if the water be boiled at a lower temperature, as in my evaporator when employing a vacuum, a greater portion dredparts of sea-water will hold 0.241 part sulphate of lime in solution. In twenty-six inches of vacuum water will vaporize at 153.

It will thus be seen that by vaporizing in a vacuum the capacity of the water for holding this salt in solution is sensibly the same as that of normal sea-water, and when the evaporator is operated in that way the precipitation of sulphate of-lime scale is almost entirely prevented. p 7 j The steam-trap F is provided for the purpose of keeping the boiler (or receiver) pressure in the coils, and the water from the trap is returned to the main boiler. The brinepump G is provided as a substitute for the :iolow-off cock, as there is a vacuum in the evaporator. The vacuum enables theopei ator to regulate the feed by the valve N without the use of a feed-pump.

If steam from the low-pressure receiver of a triple-expansion engine be used, about the same range of temperature may be utilized as hitherto, where using ordinary boiler-pressure in the coils and discharging the evapo rator against the atmosphere. For ekample,

the pressure in the low-pressure receiver is- 240-135 105 between theinside and outside of the coils. With such a range the evaporator is very efficient, as is well known.

The greater economy Will be effected when using the steam which has already been: passed through one or more cylinders, for

then its sensible heat has already been converted into work, and of the remaining total heat alarger percentage is latent and is utilized by the evaporator.

few physical means by which the latent heat of vaporization has ever been utilized.

This is one-of'the V Theyapor being generated ata lower temperature will bring over' less of organic and 0t volatile matters, and with an equal subsequent aeration will become sooner oxidized and made potable. V

Having thus d'escribedmy invention, what I claim, and desire to secure by Letters Patent, is

1. The combination of the evaporator with the air-pump and the brine-pump, substantially as shown and described.

2. The combination ot'the evaporator with the air-pump',"the condenser, and the brinepu-mp, substantially as shown and described.

3. The combination of the evaporator with ;theai-r-pump, the condenser, the feed-pipe, zan-dthe brine-pump, substantially as shown and described.

1 A. The combination of the evaporator with -the air-pump, the condenser, the filter, the feed-pipe, and the brine-pump, substantially as shown and described.

e. w. BAIRD. Witnesses:

THoM. WILLIAMSON, GEORGE W. RoUzER. 

